You are Gordon Freeman. You've just been assigned to work at the Black Mesa Research Facility. Upon your arrival, things are out of the ordinary. Computer crashes, hardware problems, a mysterious g-man, it's all odd. But you have to hurry! You're already running late, they're waiting for you Gordon, in the test chamber!

At the entrance of the test chamber you meet 2 scientists explaining what's going on today. You can already read from their conversation that something's not really ok. Yet you continue. The big test chamber houses a mysterious machine. Let's just hope that that resonance cascade the scientists were talking about, won't become a reality. Who knows what will happen? Ah! The test sample is ready.

Oh no! It's going critical! The sample, that purest sample, the problems! It's a resonance cascade! The ground trembles, lights flash, the alarms sounds, explosions follow. Suddenly, you find yourself somewhere else, you hear you heart pound and your breath stops dead in your throat, the only question you can come up with is: 'What the...?!'

Thus Begins Your Struggle...